1. Field of the Invention
The present invention is generally directed toward stamping operations and, more particularly, toward data communications for vehicle identification number stamping operations.
2. Description of Related Art
Vehicle identification numbers (sometimes referred to as VINs hereinafter), which are stamped on or adjacent the dashboard of vehicles, and must be carefully controlled to correspond, in a one-to-one relationship, with the resulting vehicles. Traditionally, the VINs are generated by a dedicated computer system, such as a mainframe computer, a central computer system, or the like (hereinafter referred to as the main computer). The generated VINs are transmitted individually, via a data communications link such as a factory-wide network, to a programmable controller provided at a remote VIN stamping center. The VIN stamping center, upon receipt of the VIN, adjusts a series of ring dies so that the desired VIN is stamped into a vehicle dashboard, and the stamping center communicates confirmation of same to the main computer. Thereafter, the main computer generates and transmits a subsequent VIN to the stamping center, and the stamping process continues.
The foregoing system works well under normal conditions. However, should there be an interruption in the network connection between the stamping center and the main computer, the VIN stamping operation is interrupted. Conventionally, if the network connection is interrupted, the VIN stamping operation must either stop, or must proceed manually. Manual operation is problematic, as it requires significant care to ensure that the appropriate VIN is selected and stamped, and to ensure that the stamped VIN is correctly recorded at the time of stamping and then later in the main computer when the network connection is restored.
In response to this problem, it has been proposed to provide a local computer adjacent the VIN stamping center. In this countermeasure, the local computer is connected to the main computer via the network connection and receives one or more VINs to be used sequentially. The local computer transfers the VINs to the stamping center PLC via a further network connection, and transfers stamped VINs (VINs used in the stamping operation) to the main computer. When the local computer has exhausted its supply of stored VIN""s, it transmits a request to the main computer, and further VIN""s are transmitted to the local computer for subsequent use.
Unfortunately, even in this improved system, if any interruption in communication is experienced, the VIN stamping operation is interrupted. For example, if there is break in the network connection between the local computer and the stamping center, of if the local computer fails, the VIN stamping operation will be interrupted. Further, if there is a break in the network connection between the local computer and the main computer, the supply of VINs to the stamping center will ultimately be interrupted.
Therefore, there exists a need in the art for a method and for a system that will insure that an interruption in communication of VINs from the main computer to the stamping center will not prevent normal stamping of VINs by the stamping center. There further exists a need in the art for method and system for locally storing stamping results in the event that data communication to the main computer is interrupted.
The present invention is directed toward a method and a system for insuring that a temporary break in communication between the main computer and the stamping center will not prevent normal stamping of VINs by the stamping center. The present invention is further directed toward a method and system for locally storing stamping results in the event that data communication to the main computer is interrupted, and for subsequent communication of stored stamping results to the main computer when data communications are restored. Finally, the present invention is directed toward a system and method comprising alternative VIN data input means to the stamping center, as may be necessary during extended or prolonged interruption of a data communication between the main computer and the stamping center.
In accordance with the present invention, a vehicle identification number data acquisition and stamping method for a vehicle identification number stamping center is provided. The method includes the steps of generating a plurality of vehicle identification numbers in a main computer, transmitting the plurality vehicle identification numbers to a programmable logic controller disposed at the stamping center, storing the plurality of individual vehicle identification numbers in an input buffer memory of the programmable logic controller, and serially accessing individual ones of said plurality of vehicle identification numbers for use in a stamping operation.
In further accordance with the present invention, a quantity of vehicle identification numbers is monitored and, when the quantity falls below a predetermined minimum, the main computer is requested to send further vehicle identification numbers to the programmable logic controller. In this manner, the programmable logic controller normally contains a quantity of vehicle identification numbers between the predetermined minimum and the predetermined maximum, the predetermined minimum being selected such that the stamping operation can continue uninterrupted even when the communications link between the programmable logic controller and the main computer is not operational.
In further accordance with the present invention, the programmable logic controller, following a successful stamping operation, transmits the stamped vehicle identification number to the main computer. When the communications link is not operational, the programmable logic controller stores the stamped vehicle identification number in an output buffer for later communication to the main computer upon reestablishment of the communications link. The output buffer is adapted to hold a quantity of stamped vehicle identification numbers that is at least equal to, and preferably significantly greater than, the predetermined maximum number stored in the input buffer to permit the stamping operation to proceed unimpeded in a manual or semi-automatic mode of operation even when the communication between the programmable logic controller and the main computer is interrupted for an extended period of time.